We just got back from an excellent holiday in the Gambia. We had intended eating out on the Senegambia strip which is the busiest tourist area and near to your hotel but in the end didn't bother as we found some great eating places in and around Kotu which avoided the need for a taxi.
We have been to the Gambia 3 times in the last 5 years, Goa 4 times and up to this visit I would have said Goa had the edge but I'm now not so sure which I would choose next !
I met another couple of HT'ers who were in no doubt that they preferred Goa but they usually stay in the South and dislike the BCC strip in Goa. They were in a Kololi hotel so really, the comparison between North Goa and Kololi are more likely to be similar although Kololi is on a much, much smaller scale. The beach alll along the coast here is far superior to the BCC strip too. You'll notice that there is far less rubbish on the beaches, in fact they are pretty clean. They are also relatively deserted too.
Don't expect beach shacks though as there aren't any. There are a few beach bars though, head towards Kotu and you will find a few along the way Kunta Kinteh is excellent but its a 30 minute walk from your hotel along the beach as pictured above.
Our hotel, the Sunset beach offers excellent value and was better than any equivalent we have stayed in while in Goa ( Marhina Dourada, Lagoa Azul, Santana Beach) but some are not as good despite the positive reports you might have read.
I can't be specific about prices nearer to your hotel but in Kotu the average beer price was 35 dalasai for a 330ml Julbrew. ( 44 Dalasai to Ã‚Â£1) You can buy cheap local spirit from the supermarket but we took some duty free gin and bought Schweppes tonic for 20D locally. Meals again vary. The choice of eating isn't as good as Goa, there are fewer places too and the prices are a bit dearer. There are not many Gambian dishes to choose, most places sell fairly simple chicken and fish dishes plus a choice of rice or chips. There are also pasta and pizza places around too, plus Indian and Chinese. We checked out the prices of the Indian and refused to pay Ã‚Â£5-6 for a paneer curry ! The food is not exceptional but very palatable and acceptable. Prices vary, and of course a lot depends on how many courses you have. There seemed to be few starters other than soup on offer so we sometimes order a main course for starters and share it, grilled squid or prawns for example plus a portion of garlic bread. The bread is around 30-50D, main courses 120D to 350D .
There are a fair few trip options but the package tour organised ones are pretty expensive and I wouldn't pay the prices. Try a local guide and /or taxi driver but always agree a price before you go. The prices that are quoted on the hotel boards are OTT and you can get much cheaper.
I hope you enjoy your hols. Don't expect it to like Goa or you will be disappointed.
I think Gambia scores over Goa in many areas, best of all there is no time difference and the flight is half the time. That alone inclines me towards going back to the Gambia first !